As a bank angler, or an angler from a small boat without electronics, what are my options to get the water temperature?

Get a pool thermometer.

 

https://www.amazon.com/s?k=pool+thermometer

 

Many of them have wireless gauges and apps.  Makes it easier to read them.

I use a digital meat thermometer. 

https://www.homedepot.com/p/ThermoPro-TP605W-Waterproof-Digital-Instant-Read-Meat-Thermometer-Food-Candy-Cooking-Kitchen-Thermometer-with-Magnet-and-Backlight-TP605W/326733999

If all you want is surface temperature a lazer gun is the way to go.  

I've been bass fishing for almost 70 years.  Tournament fishing for over 50.  I don't rely much on temperature.  I put my hand in the water.  It's hot, warm, cool, cold, real cold.  Anything else is just feel good stuff.  Really, don't do that.  Just fish the conditions as I see them.  Heck, I can guess close enough.

 

The only reason I use a temp sensor is for relative values.  It's warmer (cooler) here than over there.

Used AcuRite thermometer with probe for my live well temps worked good.

Tom

PS, put the probe down a bass throat and read body temperature is the same as the water temperature where the bass lived.

I use this little digital, has a 10’ wired remote probe I can drop down into the deep, better than just the surface temp. https://www.acurite.com/products/digital-thermometer-with-temperature-sensor-probe-00888?srsltid=AfmBOorkJhTn2DZp-p7tA9dWp2xd5GU8it0LQXAHaOSRxsCDUakUg4RN

 

 I hung a small trolling weight off the hole in the probe so it’ll sink. https://www.fishusa.com/Bullet-Weights-Trolling-Sinkers-with-Chain-and-Snap/?sku=133764